In a data processing system, user interfaces provide the way that users access the data processing system. A user interface typically includes, among other things, a keyboard and a display.
User interfaces are commonly fitted with security mechanisms to prevent unauthorized entry into the data processing system. This is particularly true in office environments where many people can easily access a user interface. One type of security mechanism locks or disables the keyboard after the keyboard has been inactive for a specified period of time. The security mechanism assumes that if the user has not engaged in any keyboard activity for some time, for example, fifteen minutes, then the user may have gotten up and walked away from the keyboard. So, after fifteen minutes has passed, the keyboard is locked to prevent any unauthorized entries or inputs by passersby at the unattended keyboard. With some type of systems, the display even goes blank to prevent sensitive information from being displayed to curious eyes. Once the keyboard locks, the user can unlock it by entering his password. This allows reentry into the data processing system through that particular user interface.
A problem with the prior art security mechanisms is that in multimedia systems the keyboard can be bypassed as an input device. The keyboard is a clumsy input device. One goal in making computers more "user friendly" is to eliminate the keyboard entirely as an input device. Therefore, voice recognition systems and touch screen systems are being employed as alternative input devices to keyboards. Voice recognition systems allow application programs to be controlled entirely by voice commands, while touch screen systems allow a user to touch icons on display screens to input commands.
Use of these non-keyboard input devices in conjunction with prior art security mechanisms causes problems because the security mechanisms do not recognize inputs from the non-keyboard devices. With a voice recognition system, for example, the user can be speaking to the user interface when suddenly the user interface is locked up by the keyboard security mechanism. Lockup occurs because the keyboard security mechanism does not recognize input from the voice recognition system. When lockup occurs, no further voice commands are accepted and the display goes blank. To prevent lockup when using the voice recognition system, the user must either remember to use the keyboard periodically, or more typically, endure the periodic lockups and reenter the data processing system when necessary. Either way, the user's concentration is interrupted, resulting in frustration and inefficiencies.
Another problem caused by the use of non-keyboard input devices in conjunction with prior art security mechanisms is the difficulty of distinguishing between a user input and a non-user input. Due to its general input properties, a voice recognition system will pick up background noise. This background noise might be accidently interpreted as a user input by the security mechanism. Such an interpretation thwarts the function of the security mechanism.